Warren Buffett may think the bottom is in for housing.Opendoor Technologies (OPEN 11.02%) stock is jumping today, but not for the same reason it had been shooting higher in recent weeks. Shares of the real estate technology company have rocketed 286% in the last month, including another 14.8% today as of 10:58 a.m. ET.Much of the recent interest has been from retail investors talking the stock up on message board forums like Reddit. Today's pop comes with real news from the company, though. Opendoor announc ...